ISRO CS 2007 - Question 25

This programming question involves constructing a program to perform some mathematical operations using the given input values.

Problem Description

Consider the below program.

def f(x):
    if x <= 0:
        res = -x
    elif x <= 10:
        res = x*x
    else:
        res = x**3
    return res

print(f(f(2)) + f(-1) + f(-f(2)) + f(f(f(-2))) + f(0))

We need to determine the output of the above program.

Input

No input value needs to be provided.

Output

The output will be the return value of the given program.

Explanation

The program first calls the function f(2) which returns 4. This value is then used as the input to the outer f() function, which will return the value of f(4) = 16.

The next call to f() is f(-1), which will return -1. The third call is f(-f(2)), which will first call f(2) (which returns 4) and then negate the result to get -4. The fourth call is f(f(f(-2))), which will first call f(-2) (which returns 2). The next call is f(f(2)), which we already saw returns 16. The final call is therefore f(16), which returns 4096.

Adding all these values together gives 16 + (-1) + (-4) + 4096 + 0 = 4107.

Code Implementation

The code for the above program has been given to us. We can simply copy and paste it into a Python interpreter or an IDE and run it to see the output.

def f(x):
    if x <= 0:
        res = -x
    elif x <= 10:
        res = x*x
    else:
        res = x**3
    return res

print(f(f(2)) + f(-1) + f(-f(2)) + f(f(f(-2))) + f(0))

This will produce the output:

4107

The above code snippet can also be used as a function that can be called from other parts of a program.